goodwin



Feb. 14, 1956 J. s. GOODWIN 2,734,427

MILLING MACHINE FOR OPERATING UPON METAL BLANKS Filed Nov. 23, 1951 8 Sheets-Sheet 1 IN V EN TOR. John 6'. Gama 601 Feb. 14, 1956 J. s. GOODWIN MILLING MACHINE FOR OPERATING UPON METAL BLANKS 8 Sheets-Sheet 2 Filed Nov. 23, 1951 INVENTOR.

Feb. 14, 1956 J. s. GOODWIN MILLING MACHINE FOR OPERATING UPON METAL BLANKS Filed NOV. 23, 1951 8 Sheets-Sheet 3 INVENTOR.

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e 0 II IIE' II Feb. 14, 1956 J. s. GOODWIN MILLING MACHINE FOR OPERATING UPON METAL BLANKS 8 SheetsSheet 4 Filed Nov. 25, 1951 Feb. 14, 1956 J. s. GOODWIN MILLING MACHINE FOR OPERATING UPON METAL BLANKS Filed Nov. 23, 1951 8 Sheets-Sheet 5 Afforney Feb. 14, 1956 J. s. GOODWIN 2,734,427

MILLING MACHINE FOR OPERATING UPON METAL BLANKS Filed NOV. 25, 1951 8 Sheets-Sheet 6 INVENTOR. 70%)? 6. 6"00 Gfddl)? BY/Q 2 2 Feb. 14, 1956 .1. s. GOODWIN 2,734,427

MILLING MACHINE FOR OPERATING UPON METAL BLANKS Filed Nov. 2:5, 1951 I s Sheets-Sheet 7 INVENTOR. john \S. 600 c/wzh Feb. 14, 1956 J. s. GOODWIN 2,734,427

MILLING MACHINE FOR OPERATING UPON METAL BLANKS Filed Nov. 25, 1951 8 Sheets-Sheet 8 INVENTOR. John 6. Goodwin United States Patent MILLING MACHINE FOR OPERATING UPON METAL BLANKS Johns. Goodwin, Whittier, Calif., assignor to Globe Oil Tools Company, Los Nietos,1Calif., a corporation oi Californi 7 v l ApplicationNovember 23, 1951, Serial No. 257,781.

27 Claims. (Cl; 90.-11.62)

This invention relatesgenerally to machine tools and particularly J33. milling machine for operating upon metal blanks or work-pieces. Specifically, the invention pertains to a milling machine attachment in the form of a present fixture is hereinafter described in connection with milling tooth spaces in such bit blanks, it is also suitable for use in holding other work-pieces in the machine.

Consequently, the term blank as hereinafter employed is to be interpreted in a broad sense as including any work-piece which is to be slotted or otherwise-milled atpredetermined, circumferentially spaced, intervals around its periphery.

Various forms of fixtures are curerntly in use for supporting work-pieces on the carriages of milling machines, the-most common fixture consisting of a pair of centers between which a work-supporting mandrel is positioned, one of the centers being operatively connected to an indexing head and being operated at the completion of each cutting stroke of the machine, to index the mandrel through a predetermined part of a revolution so as to cause the work-piece to be milled by the cutting tool at circumferentially spaced points around its periphery, as

in thecase where the teeth of gears are being milled;

With this and other forms of fixtures now in use, it is difiicult to mill surfaces which are angularly disposed with respect to the normal reciprocatory path of the milling machine'carriage and for thisreason special machine tools are required to produce, for example, the gear teeth of bevel gears. This is especially true when the proposed teeth are to be cut helically.

It is, therefore, a general object of my invention to provide a work-holding fixture adapted particularly for use on the carriage of a milling machine, said fixture' being so designed that Work-pieces, such as rock drill bits, having tapered or conical cutting'faces, may be milled at circumferentially spaced points to provide the bit teeth. A related object of the invention is to provide a fixture of this type which has a horizontal spindle'for supporting the drill bit blank, the fixture further includingmeans by which the spindle can be readily adjustedon a vetrical axis to dispose successive portions of the tapered or conical face to be milled either parallel or at an angle to the path of movement of the carriage. By the means just mentioned the cutting tool is caused to mill slots or tooth spaces which are of either uniform' depth throughout their length or of gradually increasing depth. Another object in this respect is to provide quick-,-

setting. and accurate adjusting means foradjusting the spindle angularly of the carriage so that setting up of the 2,734,427 Patented Feb. 14, 1956 work may be carried out expeditiously and with precision.

Another object of the invention is to provide a milling machine fixture having means embodied therein by which the drill bit blank or other work-piece may be rotated automatically on its axis during movement of the carriage through its operative stroke so as to produce helical tooth slots or spaces. In accordance with my invention, this object is attained through means of a difierential gear drive embodied within the fixture and operative, in response to movement of the fixture relative to the fixedbase of the milling machine, to rotate the work-piece.

Another object of the invention is to provide a blankrotating means with a change-gear mechanism by which both the rate of rotation of the work and the direction of rotation thereof may be automatically controlled to produce either left or right-hand helical bit teeth having a wide range of pitches or leads in accordance with the particular requirements.

Another important object of the invention is to provide a fixture of the type indicated which includes means" operative to prevent retrogressive rotation of the spindle and the drill bit blank carried thereby during the milling of the tooth spaces. This means consists of a separate auxiliary motor drive incorporated in the fixture and connected to the differential spindle in a manner such that it applies torque to the differential drive in a direction of its rotation or, in other words, in the direction of the helical slot being milled. By this additional driving means, back-lash, which might otherwise occur between the meshing teeth of the difierential drive due to force or thrust exerted by the milling cutter, is avoided. Chattering, or vibration which normally occurs in machine tools of this character thus is elfectively eliminated with i the result that the slots or tooth spaces are milled smoothly without presence of chatter marks.

A further object of the invention is to provide a milling machine fixture of the class referred to in which is innotches in its periphery and in which a locking latch opl eratively connected to the spindle is adapted to engage to lock the Spindle successively in difierent positions, the" number and spacing of the notches corresponding to the required number and circumferential spacing of the tooth spaces to be milled in the drill bit blank.

A further object is to provide a work-holder or fixture for machine tools which embodies index-actuating means operative in response to reciprocation of the carriage for momentarily releasing the latching means of the indexing mechanism to permit partial rotation of the indexing plate under the action of the auxiliary motor drive following each milling cut, and for thereafter causing the latch to enter successive notches of the plate just prior to each' operative stroke of the machine carriage. By this actuating means, the workpiece is positively and automatically indexed in accordance with the requirements, and this not only expedites the milling operation but eliminates wholly the chance of error on the part of the operator as is the case where the work is indexed manually .in con ventional machine tools.

A further object is to provide a fixture of the type specified which includes a control device operatively connected to the control means of the milling machine and operative to discontinue the reciprocation of the machine carriage after a predetermined number of milling cuts have been i made and the carriage returned to initial or starting posi- 1 tion, so as to bring the fixture to rest at a location where the milled work-piece may be removed and replaced by an unmilled blank and the fixture set for repeating the cycle of operation to machine the new blank. Preferably,.

the present fixture is employed in connection with a conventional milling machine having fluid pressure actuated means for reciprocating the carriage, the control device of the fixture being operable to control the actuation of valves in said fluid pressure means.

Another object of the invention is to provide a machine of the character described characterized by an improved indexing machine by which the work can be indexed to any desired degree and is not limited in the manner common to usual indexing mechanisms.

A still further object of my invention is to provide a self-indexing work-holder or fixture for machine tools which is relatively simple in construction and universal in operation and one which functions with great precision to effect either straight or helical milling, the fixture being particularly adapted for use in milling the unevenly spaced teeth of earth boring bits.

The present invention contemplates utilization of a machine which is preferably in the nature of a conventional milling machine. This milling machine is, in a typical case, characterized by a slidably supported carriage and includes means serving to reciprocate the carriage. The milling machine further includes a cutter-carrying spindle and a drive therefor and means for etfecting reciprocation of feed of the spindle. Further, in a typical case the milling machine has or includes a control system coordinating the action of the various working parts of the machine.

By the-present invention a structure or attachment is provided .on the carriage of the milling machine and this structure is characterized by a principal part or frame, preferably in the form of a housing. The housing is attached to the carriage for adjustment relative thereto and is normally set in a fixed position relative to the carriage. A work holder, preferably in the form of a spindle, is rotatably carried by the housing to support a blank which is to be acted upon by the tool of the machine, and a power means is provided applying torque or driving force to the spindle. A control means governs or checks rotation of the spindle that carries the blank and coordinates the movement of the carriage with that of the spindle carrying the blank. An indexing means is provided to establish the rotative position of the spindle at the beginning of the work cycle and a means is provided whereby the indexing means operates at the termination of each work stroke to effect setting of the blank carrying spindle in position for the next operation. A lock means, preferably manually operable, is provided for locking the work carrying spindle against rotation, when desired, and a control system relates the elements or action of the milling machine to the action of the structure carried by the carriage of the machine.

The various objects and features of my invention will be fully understood from the following detailed description of a typical preferred form and application of the fixture, throughout which description reference is made totheaccompanying drawings, in which:

Fig. 1 is a front view of a typical preferred form of the improved work-holder or fixture, showing it combined. with a conventional milling machine. Fig. 2is an enlarged.

endelevational view of a part of the structure shown in Fig. l and as viewed in the direction of arrows 2-2 on Fig. 1. Fig. 3 is a further enlarged longitudinal sectional view through the fixture, taken substantially as indicated byline 3-3 on Fig. 2. Fig. 4 is a perspective view of a typical work-piece which may be milled while held in the fixture, this work-piece beinga conventional earth boring bit as used in drilling oil wells. Fig. 5 is a plan view of the fixture and the associated parts of the milling machine. Fig. 6 is a cross-sectional view of the auxiliary power means taken substantially as indicated by line 6-6 on Fig. 3. Fig. 7 is a cross-sectional view of the differential drive being a view taken. as indicated by line 7-7 on Fig. 3. Fig. 8 is a cross-sectional view taken as indicated by line 8-8 on Fig. 3. Fig. 9 is a sectional plan view of the gear train forming part of the differential driving means for 4. the work-supporting spindle, taken as indicated by line 9-9 on Fig. 3. Fig. 10 is a sectional plan view of the speed-changing and reversing gear means incorporated in the differential drive, taken as indicated by line 10-10 on Fig. 3. Fig. 11 is a view similar to Fig. 10, showing the arrangement of gears for etfecting reverse and faster operation of the differential drive. Fig. 12 is a vertical sectional view, taken as indicated by line 12-12 on Fig. 11. Fig. 13 is a longitudinal sectional view through the spindlelocking means, taken as indicated by line 13-13 on Fig. 5. Fig. 14 is a sectional plan view of the latching means for retaining the indexing plate and associated components locked against rotation during the operative stroke of the milling machine carriage, taken as indicated by line 14-14 on Fig. 8. Figs. 15 and 16 are views similar to a portion of Fig. 8, showing various positions of the indexing latch mechanism. Fig. 17 is a vertical sectional view of the locking devices for the index latching means, taken as indicated by line 17-17 on Fig. 14. Figs. 18 and 19 are views similar to Fig. 17, showing other positions of the locking devices. Fig. 20 is a cross-sectional view taken as indicated by the line 20-20 on Fig. 18, and Fig. 21 is a diagrammatic view illustrating the electrical and pressure fluid control system for the milling machine and the various components of the self-indexing fixture.

The structure that I provide on or combine with the elements of a milling machine involves, generally, a housing structure A in or on which the various elements or.

mechanisms of the structure are located and which is rotatively mounted on or combined with the reciprocating carriage or table B of the milling machine C for angular adjustment relative thereto, and work-holding means D in the form of a horizontal spindle or mandrel rotatably carried by the housing for supporting a blank to be milled. A power means H is provided supplying torque or driving force to rotate the spindle. rotation of the spindle from the milling machine carriage during the movement or stroke of the carriage so as to effect milling of helical grooves or slots in the work-piece. The means E includes, in series, a planetary drive mechanism 24 on the spindle 85, preferably a change gear mechanism 23 for controlling both the speed and direction of operation, and a rack'and pinion means 22 between the.

change gear mechanism 23 and a stationary part of the milling machine C. The power means H applies torque to the spindle against the controlling action of control mechanism E, so as to take up any slack or back-lash which might otherwise occur between the carriage B and workholding means D. Indexing means I is provided for index-.

ing the spindle having the work-piece thereon prior to the.

travel or driving thereof through a working stroke. The means I includes a releasable latching mechanism 21 having a dog successively engageable in index notches in aplate and. serving to normally lock the mechanism of means I. When the dog is released the mechanism of means I is freed to be operated'by power from means H. The structure also includes fluid pressure actuated means L operativewhen the carriage reaches the end of its stroke to release the dog of the latching mechanism to allow indexing'of the mechanism of means I. Manually operable locking means M is provided for locking the spindle controlling mechanism E against rotation, when the gear-andrack 22 is disconnected and when it is desired to produce. The invention.

straight milling cuts in the workpiece. further includes control means N, cooperating with.ele-

ments ofthe milling machine, to control the action of the carriage of the milling machine relative to the action of structure carried by the carriage.

The milling machine C that I refer to may be more or less conventional in form and the machine shown has a base or bed 65 from which projects a pair of vertical posts 66. Carried by the posts 66 is a head 67 in which a horizontally disposed tool spindle or arbor 68 is adapted to be rotated from a motor M contained in the base through themedium of a conventional driving gear mechanism A control means E governs- (Fig. 21). As shown best in Fig. 2, the tool spindle .68 has a projecting end carrying amilling cutter-70. which,;

for the purpose of milling blanksof the character to be later described, is preferably an end mill of conical-form. The spindle-68 has acollar or head 72 to which is pivotally connected the lower end of a feed lever 73. This lever is pivoted at 74 to the upper end of the head 67, an. inter fluid pressure actuated means serving to feed the milling cutter or to position it relative to the work upon which it operates. In practice, stop means (not shown) such as is common in milling machine construction serves to limit the movement of the spindle 68;

'When pressure fluid is introduced into the rearward end of the cylinder 77, the piston rod 75 is forced outwardly so as to project the cutting tool 70 to a stopped posi* tion in the path of blank carried by the table B, and when pressure fluid is introduced into the forward end of the cylinder, the cutter 70 is retracted for the purpose.

to be later explained indetail.

The table or carriage B of the milling machine is reciprocated relative to the milling cutter 70 through the medium of a fluid pressure actuated means 19 including cylinder 80 (Fig. 21), which is mounted on the bed 65. A piston 81 slidable in thecylinder 80 operates a rod 82 which is connected by an arm 83 to the carriage B so'that when pressure fluid is introduced alternately into the ends of the cylinder 80, the carriage is reciprocated. Means, to be later described, is provided for controlling the rate of travel of the carriage B during its working and return strokes. The control system of or incorporated in the milling machine will be hereinafter described.

The base element or housing A includes a base 25 which is generally circular in plan configuration. One

side portion is shown flattened, as indicated at 26, to clear parts of the milling machine. The base 25 has aflat bottom resting on the carriage and is attached to the carriage by a plurality of bolts 27, the heads of which are engaged in the longitudinal T-slots 28 in the carriage 8., Nuts 29 are screwed onto the upper ends of the bolts 27."

and against the top of the base 25 and when tight secure the base in place on the carriage.

annular rim or boss 32 that supports partsof the housing hereinafter described.

The housing A also includes a case section 35 which, as shown in Figs. 3, 5, and 6, has a lower circular por tion 36 provided with an annular finished edge 37' rest-v ing upon the annular rim 31 of the base 25. The portion 36 has a large, central, downwardly projecting boss 38 which is received in the recess of the base 25 to adapt the housing section for rotation relative to the base. Clamping elements 40 are provided for securing the case section 35 to the base 25. A pair of elements 40 is carried at the forward end of the base 25, each elebe clamped by means of screws 41 screwed into the casesection instead of the base.

The case section 35has a vertical forward wall 42,.

spaced rearwardly of the vertical axis of rotation of the case and vertical side walls 43 and 44, the section having a rearwardly projecting horizontally disposed tubular portion 45. A horizontal partition 46 defines, with the for- The central portion. of the base 25 has a circular recess 30 in its upper side, the recess being bounded by an upstanding annular rim or a support 31; The baseis also provided with an outer ward and side walls 42, 43, and 44,.andant1pstanding; wall 47, an upperphamber-or compartment :48. This compartment'is normally closed by ,means of -a,cover 50 hinged to the upper end of the front wall 42 by meansof-- a pin 51, and is locked to the wall 47 by means of a; latch-bolt 5 2 pivoted at 53. Latch-bolt 52 engages in a slot provided in the cover. As shown in Figs. 1 and 7, the sides of the tubular portion 45 have access openings v 54 which normally are closed by removable plates, 55. The rearward endof the tubular portion 45 of the case section 35 has a finished annular .pad or boss 57 on which is mounted a rear, box-like housing section 58. Section- 58 is secured in place by means of bolts 58 (Fig. 5), The housing section 58 has a forward wall 59, provided with a bearing boss 60, and has a detachable rear wall;v 61, in the form of a coverhaving a central aperture 62.

With the structure just described the base of the housing A can be fixed to the carriage B and thecase of the housing can'be fixed on the base in various rotative positions as circumstances require. The work-holding means D includes. a horizontal spindle which, as best shown in Fig. 3, is mounted; for rotation within .the housing cases 35 and 58 and has; a work-holder projecting from the case and adapted to carry a cutter. To mount the spindle 85 for rotation, the front wall42 of the case section is provided with a large; bearing boss 86, the outer and inner ends of which are, counterbored to receive anti-friction bearings such as roller bearings 87 and 88, respectively. The bearings 87 and 88 rotatably support the forward end of thespindle' 85 and are adapted to take the axial thrust of the spindle. A scaling'ring 89 is employed for preventing escape of, lubricant from the front endof the housing or the en-;: trance of material into the housing. The rearward end: of the spindle '85 is journaled in the bearing boss. 60 of the case section 58 through thrust-type roller bearings92- and 93 and other components to be later described.

As previously stated, the structure being described. is particularly adapted for use in supporting blanks from;. which earth-drilling bits are to be formed. Such bits are in many cases conical and frequently have a plurality: of concentric rings of cutter teeth which may extend, either parallel with or helically with respect to the rotative axis of the bit. or cutter. For example, the bit 95 ;v

may take the form illustratedin Figs. 3 and 4.in which case it isprovided with three sets 96, 97, and 98, of cutter; teeth. The teeth of the sets 96 and 97 may be cut. on; true radial lines while the teeth of the other or largest set 98 may be cut helically, the present fixture. being adapted to produce both types of bit teeth, as later explained. The bit 95 is mounted-or fixed ion an elongate adapter 95 which has a tapered portion 99 to adapt it; to fit into a similarly tapered socket100 in theforward': end of a bore 101 that extends longitudinally through the spindle 85. The adapter 95 is releasably secured to. the spindle by releasable fasteners 95 engagedwith a; flange 95 on the adapter. A bolt 102 suitably anchored; to the bit extends rearwardly from. the bit through the adapter 99 and through the bore 101 to the rear endof the spindle and is drawn rearwardly by means'of 'a nut 103 screwed onto the bolt and against a washer'104 abutting the rear end of the spindle 85. This holds the Work or hit tight relative to the adapter and spindle.

The general arrangement or relationship of the ele-; ments thus far described is shown best in Figs. 3 and 5;. of the drawings. The horizontal axis of the cutter car-w rying spindle intersects that of the work or blank carrying spindle. The cutter carrying spindle can be fed in or positioned to gain the desired depth of cut and the blank carrying spindle can be set in various angular positions relative to the cutter carrying spindle. For example, the spindles can be set at, right angles, as shown in Fig. 5, in which casea cut is made parallel with the axis of A the blank when the carriage is moved to feed the blank relative to the cutter. Should the blank carrying spindle berotated as'the carriage feeds the cutter will make a ina direction other than parallel with the axis of the blank.

In order that the milling cutter 70 may mill the teeth crests 97 parallel to the line XX in'Fig. 3, his necessary that the bit blank be arranged and moved to travel relative'to the milling cutter 70in the direction of the line X'-X'. The general setting is accomplished by positioning the case-structures 35 and 58 at the proper angle relative to the base 25, after which the clamping elements 40 are tightened to retain the bit blank in the required position. When the teeth of the set 98 are to be milled, the housing is adjusted to a'position wherein the axis of the spindle SScXtends parallel'to thepath of movement of the table B, as shown in- Fig. 5.

When the teeth of the bit blank are to be cut helically. it will be apparent that the blank must be rotated through apart of a revolution during its travel relative to the milling cutter 70, the degree of turning of the blank per-increment of its travel determining the lead or pitch of the helical cut. The structure embodies means for effecting such partial rotation of the bit blank to produce the helical bit teeth, this means consisting of the means H and means E hereinafter described.

in accordance with the present invention power means H provides a yielding drive for rotating the blank carrying spindle 85. Referring to Figs. 2, 3, 5,- and 6, the

means H includes a reversible fluid-actuated motor 180 which is mounted on a section 13 of'the side 43 of the case. Section 43 rests on a ledge 181 of the case. The power shaft 182 of the motor extends downwardly through a hole 183 in the ledge where it is joined to a shaft 184 by means of a coupling 185. The shaft 184 is supported in rollerbearings 187 located at the inner side of the housing wall 43 and carries a' worm gear 188. The worm gear 188 meshes with the teeth of a worm wheel 189 which is mounted on a tapered portion 190 of the spindle 85 and held tightly in place on the spindle 85 by means of a nut 191 (Fig. 3).

The means E serves as a control for and in effect regulates or checks the action of means H. Further, the means E is coordinated with the carriage so that thccontrolling action is coordinated with the action of the carriage. The function or action of means E will appear from consideration of the mechanisms that enter into or which make up means E.

The planetary drive mechanism 24 of means E is best shown in Figs. 3 and 7 of the drawings. shouldered portions of the spindle 85 is a pair of roller bearings 14.17 upon which is rotatably mounted a spider or floating ring member 188. Secured to the member 108, 'as by screws 109, is a bevel ring gear 110 which meshes with a bevel pinion 111 on a shaft 112 which is journaled in roller bearings 113 held in a vertical opening in the partition 46. The shaft 112 is operated from the mechanism 23 hereinafter described.

The floating member 108 carries a pair of stub shafts 114 projecting radially inward from the member 108 towardthe axis of the spindle 85. Rotatable on the stub shafts-are bevel planet gears 115 which mesh with a bevel sun gear 116 keyed at 118 to a tapered portion 117 of the spindle 85 and retained axially in place by a nut 11.9 screwed onto a threaded portion of the spindle 85.

A second sun gear 120 which is normally fixed or stationary is keyed at 121 to the tapered end 123 of a'hub member 124 forming part of the indexing means I, to be later described. The gear 120 is retained axially on the member 124 by a nut 125. Assuming that the gear 120 is held stationary, by means to be later de: scribed, and that power means H is rotating the spindle 85. and, therefore, gear 116, the planet gears 115 will move bodily about the spindle 85 as they rotate on Positioned on their axes and'will rotate-the fioating'member 108. As the'floating member rotates, the ring gear thereon causes rotation of pinion 111 and the shaft 112 carrying pinion 111. When the sun gear is released for rotation it may be drawn or turned through the gear mechanism just described.

The change gear mechanism 23, which is illustrated in Figs. 3 and 6, and 9 to 12, may or may not be incorporated in the structure as circumstances require. Mechanism 23 provides a drive between shaft 112 and shaft 141. With one gear arrangement, the shaft 112 rotates in one direction relative to shaft 141, whereas with another gear arrangement shaft 112 rotates in the opposite direction relative to shaft 141. 10, mechanism 23 includes a gear which is keyed to the shaft 112 above the partition 46, the upper end of this shaft being rotatable in a ball bearing 131 held in a plate 132 fixed in chamber 48. The gear 130 meshes with a gear keyed to a vertical shaft 146 journaled in bearings held in the partition 46 and the plate 132. To the upper end of shaft 146 is keyed a gear 147 which is adapted to mesh with a gear 140 on a transfer shaft 141. With the gear 147 mounted on shaft 146 and meshing with gear 140, the pinion 111 is allowed to rotate in what may be termed a forward direction. To gain a reverse operation, the mechanism is as shown in Figs. 9 and 11. The gear 130 meshes with a reversing idler gear 133 on a vertical shaft 134 journaled in bearings in the partition 46 and the plate 132. The idler gear 1.33 meshes with a gear 135 keyed to a vertical shaft 136 journaled in bearings 137 in the partition 46 and the plate 132. This shaft projects above the plate and carries a gear 139 held by a key 138. The gear 139 is mounted on shaft 136 so that it meshes with the gear 148 keyed to the upper end of the vertical shaft 141.

It will be readily understood how the gear 139 may be positioned on shaft 136 or 146 in order to gain.

the desired direction of rotation as circumstances require. The means22 is characterized by a rack and pinion mechanism and connects the carriage B and mechanism 24 through mechanism 23 when mechanism 23is employed. Mechanism 22, as shown in Figs. 5 and 6, involves the transfer shaft 141 connected with the mechanism 23. Shaft 1.41 is rotatable in a bearing 150 in the plate 132 and a bearing 151 in an internal boss 152 in the housing section 35 (Fig. 6). Keyed to the lower end of the shaft 141 at 153 is a pinion 155 which, as shown in Fig. 5, meshes with a gear 156 rotatable on a roller bearing 157 surrounding a boss 158 depending from the center of the circular forward portion of the case section 35. The gear 156 meshes with the teeth of a-rack 160 secured to the head 67 of the milling machine C, which rack extends parallel to the path of'movement of the table B.

It will be apparent that when gear 147 is used and when the table B is moved forwardly during a cutting operation, the gear 156 rolls along the fixed rack 160 and thus rotates as does the gear 155 and the transfer shaft 141. This will result in rotation of the blank carrying spindle in one direction by power means H so that a helical cut'is made in the blank having a lead:

inone direction. When the gear 139 is used, the shaft 1'l2'also rotates in the opposite direction so that the spindle 85 rotates causing the helical cut to lead in the opposite direction. The rotation of the spindle 85 is in each case slow due to the gearing selected. the particular arrangement or selection of pairs of speed changing gears140-147 and 139-148, as shown in Figs. 10 and 11, the spindle 85 may be turned at a slower or faster rate per increment of linear travel of the table B as desired.

In the event that the bit teeth are to be milled straight orparallel with the axis of the blank, instead of helical As shown mainly in Figs. 9 and 9 gear 140 is removed from the shaft 141 to disrupt the drive from the rack-and-pinion means 22 to the spindle 85. The locking means M, when then engaged, prevents rotation or operation of member 108 of mechanism 24. Referring to Figs. 5, 7 and 13, the locking means M is located on the tubular rearward portion 45 of the case section 35 in transverse alignment with the rearward portion of the member 108. This locking means includes a sleeve 165 which projects through a hole in the tubular portion 45 with a peripheral flange 166 resting against a boss on the extension of portion 45. The upper end of the sleeve 165 is threaded to receive a thimble-like cover 167 which is screwed thereonto. A locking plunger 168 is slidable axially within the sleeve 165 with its upper end projecting upwardly through an aperture in the upper end wall of the cover, this end of the plunger carries a knob 170. The opposite or lower end of the plunger is reduced in diameter to provide a locking lug or key 171 which, when the plunger is in its lower position, as illustrated in Fig. 13, engages in one of a plurality of slots or keyways 172 provided in the periphery of the rearward portion of the member 108 to lock the latter against rotation.

The plunger 168 is yieldingly urged downwardly to said locking position by means of a coil spring 174 compressed between a shoulder of the plunger and the upper end wall of the cover 167. The cover 167 is threaded on sleeve 165 and can be set to engage a shoulder 167 on plunger 168 to positively hold the plunger in locking position. In order to retain the locking plunger 168 elevated or unlocked, as when the spindle 85 is to be rotated to produce helically milled teeth, the plunger is provided with a radial pin 175 which operates in a bayonet slot 176 formed in the side of the sleeve 165. By lifting the plunger 168 and then turning it by means of its knob 170, the pin 175 is caused to enter the transversely extending portion of the bayonet slot 176 to retain the plunger in non-locked position.

It will be apparent from the description of means E that during reciprocation of the table B the spindle 85, together with the bit blank thereon, is oscillated in timed relation to the carriage, so as to mill the helical bit teeth. Milling machines and similar machine tools for cutting such teeth have the disadvantage of allowing back-lash in the driving mechanism and this causes vibration between the milling cutter and the work, resulting in uneven milling of the teeth and the presence of chatter marks on the teeth.

Assuming that the spindle 85 is rotated in a clockwise direction by the means H to produce a tooth of lefthand helix, the fluid motor 180 functions through the worm 188 and wheel 189 to apply torque to the spindle 85 in said clockwise direction while at the same time the means E checks or controls such rotation responsive to the movement of the carriage B. Under this condition there is, in effect, always an excess of torque pressure tending to rotate the spindle 85, and, consequently, any and all play or looseness of the mechanism is taken up and the structure is mounted tight and free of play that would othewise result in chatter or looseness. Also, the torque producing fluid motor 180, acting through the transmission means E and the rack-and-pinion drive means G,-assists the milling machine table B in its travel. When the work stroke is completed and the carriage B is being returned the motor 180 is reversed through the action of the control system hereinafter described. Operation of the fluid motor 180 is reversed depending upon which way the spindle 85 is being operated and a reversing switch 250 is provided for the motor 180.

The indexing plate means I is employed to gain indexing of the work-holding spindle 85 following each milling stroke of the carriage B so as to cause the milling cutter 70 to mill successive teeth on the periphery of the bit blank in accordance with the requirements. The

means J, which is shown in detail in Figs. 3, 8 and 1416" 20, includes an indexing ring or plate 195 secured to the rear end of an indexing hub member 124 by means of screws 196. The hub 124 is rotatably carried in bearings 92 and 93 supported in case section 58 and it has an means of the screws 196 so that a ring of the desired character can be installed as circumstancesv require. While the slots of the ring 195 are shown evenly spacedaround the periphery, they may be unevenly spaced when the bit teeth are to be likewise spaced apart.

Pivoted on a stud 199 held in the wall 59 is'an index latch 200. The latch 200 extends downwardly along the periphery of the index ring or plate 195 and has a later-- ally projecting lug 202 which is adapted to engage in the index slots 197. The latch is yieldingly urged in a counterclockwise direction by means of a spring 204 seated in a socket member 205 on the side of the housing portion 58 (Fig. 8) and engaging the side of the latch. The lug 202 is thus normally held in one of the slots. Pivotally connected to the lower end of the latch 200, by means of a pin 206, is one end of a latch link 208. The

other end of the link 208 is pivotally connected to the end of a piston rod 210, forming part of the fluid pressure actuated means L. At one side of its bifurcated end, A

the link 208 has a lateral projection or lug 211.

The fluid pressure actuated means L includes a cylinder 212 which is pivoted on a cross pin 213 extending between fixed ears 214 on a wall of the housing section 58. The piston rod 210 has a piston head 215 which is slidable within the cylinder 212. The opposite ends of the cylinder 212 are connected by fluid lines 216 and 217 to control means to be later described. When fluid under pressure is introduced into the right-hand end of the cylinder, the rod 210, acting through the link 208, pivots' the latch 200 in a direction to withdraw its lug 202 from 'the index slot 197 in which it has been engaged.

The pivoted cylinder with piston rod 210 projecting therefrom and the link 208 connecting the rod and latch form a toggle which is normally substantially straight, as shown in Fig. 8, with the lug 202 normally engaging in an index slot 197 to retain the ring 195, the hub 124 and gear against rotation so as to effect rotation of the spindle 85 in the manner previously explained.

A lever 220 pivoted on a fixed pin 221 is controlled" by the plate 195, and normally holds the aforementioned.

toggle in the straight position, as shown in Figs. 15 and 18. The arm 220 of lever 220 has an obtusely pointed lug 225 which rides on the periphery of the plate and is adapted to enter a slot 197 as does the indexing lug 202. A spring 226 connected between the lower arm 220 of lever 220 and to an anchor stud 227 on the housing section 58 normally acts to pivot the lever 220- in a clockwise direction so as to urge lug 225 toward the plate. The lower end of the arm 220 has a hori lug 211 so that the toggle is held aligned.

During forward movement of the carriage B the components of the indexing means J assume the relative positions shown in Fig. 8, at which time the lug 211 of the toggle link 208 overlies the upper flattened end 230 of a pivoted latch-like locking element or plate 231, as shown in Fig. 17. The locking element 231 is pivoted on a stud 232 and normally is urged in a countercloclo, wise direction by a spring 233, this pivotal movement being limited by the engagement of an end 234 of the zontally projecting pad 228 that normally supports the element against the bottom wall of the housing section 58. The locking element 231 retains the lug 211 elevated and thus prevents breaking of the toggle. When the lug 211 is in this position, it underlies a guide plate 235 which is attached to a boss 236 on the forward wall 59 of the case section 58 (Fig. 14). The free end of the guide plate 235 has an inclined cam edge 236 which overlies the pad 228 of the arm 220.

As the machine operates and after the carriage B completes its forward or working stroke its movement is reversed. At a selected position of the return movement of carriage B control means N operates so that pressure fluid is introduced into the right-hand end of the latch cylinder 212 to force the piston rod 210 toward the left. The rod 210, acting through the link 208, functions to pivot the latch 200 in a clockwise direction so as to withdraw lug 202 from the index slot or notch 197 in the index plate 195, as illustrated in Fig. 15. During this movement of the link 208 lug 211 rides along the lower edge of the guide plate 235 and the cam edge 236 acts to depress the lug slightly until it rests directly upon the pad 228 of the arm 220. Thus, the toggle is broken slightly but not completely since the lug 211 now comes to rest upon the pad 228 adjacent a vertical edge thereof as shown in Fig. 18. Under this condition the index plate 195 is free to rotate under the action of the power means H and upon initial rotation of the plate the pointed projection 225 of the arm 220 is cammed out of the slot 197 to cause the lower end of the arm to pivot toward the right, as viewed in Fig. 16, causing withdrawal of the ledge 228 laterally from beneath the lug 211.

With the pad 228 released from beneath the lug 211, the pressure in cylinder 212 acts to break the toggle 208, 210 downward whereupon the latch 200 is pivoted in a counterclockwise direction to cause its lug 202 to engage the periphery of the index plate 195 which is rotated by the fluid motor 180. When the next index slot 197 of the plate 195 registers with the lug 202, the lug is caused by spring 204 to enter this slot to lock the plate against further rotation and in its newly indexed position. The arm 220 is also pivoted under the action of the spring 226 to cause its projection 225 to enter the index slot 197 and its ledge 228 to return to locking position. When lever 200 engages the index plate, the arm 242 operates switch 240 to complete the circuit and reverse the table. immediately thereafter the piston rod 210 is drawn into the cylinder 212 to straighten the toggle 208, 210 and during this action the lug 211 of the link 208 moves in an arc which is represented by the long arrow in Fig. 19 passing beneath pad 228.

During this arcuatc travel of the lug 211, it rides along the vertical edge of the locking plate 231 which may yield against the action of spring 233 to permit this movement. As the lug 211 arrives at its upper position, slightly beyond the position illustrated in Fig. 19, the upper portion 230 of the locking plate 231 snaps beneath the lug (Fig. 17) to again lock the toggle in the substantially straight or extended position which it maintains during the next working stroke of the carriage B. The indexing means I thus functions automatically at the end of each return stroke of the carriage B to index the spindle 85 and the work-piece thereon in readiness for another milling cut. I

The milling machine includes, generally, a control system whereby the working parts are controlled so that when the machine is set in motion or operation the carriage makes a work or cutting stroke and returns, and the cutter carrying spindle is rotated and is fed out to a working position and is then returned.

To start the milling machine from -a starting position where the carriage is at the extreme left, a manual switch 293 is closed momentarily. This closes a circuit to a solenoid 290 which positions a valve 267 which controls flow of fluid under pressure to the means 19 that operates the carriage and the means 20 that feeds the cuttercarrying spindle. Fluid under pressure is supplied from a suitable source such as a pump 263 receiving fluid from a reservoir 262. A line 265 conducts fluid under pressure to the left hand end of cylinder causing the carriage B to proceed in a direction to feed the blank to the cutter. The line 265 also supplies fluid to the cylinder 77 so that the cutter carrying spindle 68 is fed to working position. A suitable sequence valve 265 is provided so that cylinder 77 is supplied with fluid to operate piston '76 before fluid is supplied to cylinder 80 to operate piston 81. The motor M' driving the spindle 68 may run continuously. Exhaust from cylinders 80 and 77 is carried by a line 266 through valve 267 to a variable choke or metering device 273 which regulates the speed at which the carriage advances. Valve 267 has four positions-a first position for rapid travel of the.

carriage to the right, a second position for slow travel to the right, a third position for rapid travel to the left, and a fourth position for slow travel to the left.

When the carriage reaches the end of its desired stroke to the right, a cam 2S0 closes a switch 285 completing a circuit to a solenoid 236 which operates valve 267 to a reversed position so the means 19 and 20 are reversed causing the carriage to return toward the starting position and the cutter carrying spindle to be retracted. A metering device 272 like the device 273 controls the rate of return.

In the structure illustrated the valve 267 is such as to cause flow through the metering or throttling devices 272 and 273 when desired, or to by-pass these devices when rapid movement is desired. The valve 267 has a stem 268, and a cam 281 on the carriage operates the stem and causes the valve to move to a position where flow is through a throttling device resulting in slowing down of the carriage just prior to the bit blank reaching the cutter. During the return stroke a cam 282 on the carriage 0perates the valve to eflect slowing down of the carriage just before it reaches its indexing position. The indexing operation occurs as the carriage completes its return movement and as soon as the indexing is completed the switch 240 operates solenoid 290 so that the carriage starts on another cycle of operation or feeding movement even though it has not fully returned to the starting position.

Motor is a reversible motor under control of a reversible control valve 260, the action of which is responsive to a solenoid 261 in the circuit of means N. A reversing switch 251 in the circuit to the solenoid 261 is operated by a cam 252 on the stem 268 of valve 267 so that reversal of motor 180 occurs simultaneously with reversal of the carriage. The selector switch 250 in the circuit to solenoid 261 is provided so that the motor 180 operates in the proper direction relative to movement of the carriage.

The control means N is shown in Fig. 21 as including, in addition to the starting switch 293, a switch 240 which is closed by an arm 242 projecting from latch 200 so that it is closed at the end of each operation of means I which follows return of the carriage to starting position. Switch 240 is in parallel with switch 293 and thus starts operation of the mechanism each time it is closed.

When the carriage has made its work stroke and has returned to starting position, a cam 283 operates stem 275 of a valve 274 which controls fiow of fluid from pump 263 to the cylinder 212 that operates the latch mechanism 21 of means I causing the latch to be released and the indexing means to operate. When means I has completed its operation, switch 240 is closed as above described, starting a new cycle of operation.

A normally closed stop switch 241 is in series with switch 240. A cam 245 on plate opens switch 241 when the plate has moved through one revolution or in a manner to effect the desired number of cutting operations. When switch 241 is opened the table goes to the end 13 r of its travel to the left, or to the starting position, and stops until the machine is manually started.

When the carriage starts operation the stem 275 is released and valve 274 operates so that the cylinder and piston for the means 21 is reversed, causing the toggle to be returned to normal starting position.

The entire machine is under control of a master switch 292 and the pump 263 is operated by a motor 264.

The improved machine tool having been described in detail, the mode of operation thereof is explained briefly as follows: To mill the teeth in a bit blank, the latter is first secured to the forward end of the spindle 85, and if the crests of the teeth are to be generated parallel to the axis of the spindle, the fixture is adjusted to cause the spindle 85 to extend parallel to the longitudinal plane of the table B. An index plate 195 having the required number of index slots and spacing is selected and applied to the hub 124. Assuming that the teeth on the work-piece are to be of right-hand helix, the proper gears are employed in the means 23 to produce the required direction of rotation of the spindle 85 during travel of the carriage B through a milling stroke, the gears selected being adapted to effect the required speed ratio between the rotation of the .spindle and the travel of the carriage so as to produce a helical milling cut of predetermined lead. When helical teeth are to be cut, the lock 171 is retracted to allow turning of the spindle. After the milling cutter or end mill 70 is applied to the arbor 68, the machine tool is ready for operation and this is effected by simply closing the switch 293. As above described, the machine will continue in operation until the desired number of cuts have been made, whereupon it will stop. The operator then removes the work-piece 95 from the spindle 85 and replaces it with a new blank, after which the machine is restarted.

In the event that the teeth are to be cut with reverse spiral, for example, left-hand pitch, it is only necessary to change the gear position of mechanism 23. When straight teeth, having no spiral, are to be milled, no gear is mounted on the shaft 141. To positively prevent rotation of the spindle 85, the locking plunger 168 is turned to release its pin 175 so as to allow the locking key 171 to enter a slot 172 of the spider member 108.

It will be observed from the foregoing that my invention provides a machine tool which is fully automatic in its operation of milling rock-boring bits, or the like. The holder or fixture for the work-piece is universal in use and'may be readily adjusted to adapt the machine to mill either straight or spiral teeth of the desired leftor righthand lead. As a particular feature of improvement, the work-holding fixture is self-indexing, its operation being controlled in sequence with the reciprocation of the machine table. The indexing means is positive in action and fully adjustable by simple means. Having described only a typical preferred form and application of my invention, I do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to myself any variations or modifications that may appear to those skilled in the art.

Having described my invention, I claim:

1. In combination, a bed, a power driven cutter on the bed, a carriage mounted on said bed for reciproca-- tion relative to the cutter, a drive adapted to operate the carriage, a spindle rotatably mounted on the carriage and adapted to rotatably carry a work piece, means adapted to apply torque to the spindle to yieldingly rotate it, and a governor connection between the bed and spindle adapted to coordinate rotation of the spindle with movement of the carriage and thereby limiting rotation of the spindle.

2. In combination, a bed, a carriage mounted on said bed for reciprocation, a drive adapted to reciprocate the carriage, a work carrying spindle mounted to rotate on the bed, means adapted to apply torque to the spindle to yieldingly rotate it in one direction, and a governor 14 connection between the bed and spindle adapted to coordinate rotation of the spindle with movement of the carriage and including a positive gear train limiting rotation of the spindle in the said direction.

3. In combination, a bed, a carriage mounted on said bed for reciprocation, a drive adapted to reciprocate the carriage, a Work carrying spindle mounted to rotate on the bed, a fluid pressure actuated drive adapted to apply torque to the spindle to yieldingly rotate it in one direction, and a governor connection between the bed and spindle adapted to coordinate rotation of the spindle with movement of the carriage limiting rotation of the spindle in said direction.

4. In combination, a bed, a carriage mounted on said bed for reciprocation, a drive adapted to reciprocate the carriage, a work carrying spindle mounted to rotate on the bed, a reversible fluid pressure actuated motor adapted to apply torque to the spindle to yieldingly rotate it in a given direction, and a governor connection between the bed and spindle adapted to coordinate rotation of the spindle with movement of the carriage and including a positive gear train limiting rotation of the spindle in said given direction.

5. In combination, a bed, a carriage mounted on said bed for reciprocation, a drive adapted to reciprocate the carriage, a work carrying spindle mounted to rotate the bed, means adapted to apply torque to the spindle to yieldingly rotate it in one direction, and a control means governed by movement of the bed relative to the spindle and regulating rotation of the spindle and including a gear train connected to the spindle and a rack and pinion mechanism operated by the bed and connected to the gear train to limit rotation of the spindle in said direction.

6. In combination, a bed, a power driven cutter on the bed, a carriage mounted on said bed for reciprocation relative to the cutter, a drive adapted to operate the carriage, a work carrying spindle adapted to rotate, means mounting the spindle on the carriage in selected relation to the cutter, means adapted to apply torque to the spindle to yieldingly rotate it in one direction, and a governor connection between the bed and spindle adapted to coordinate rotation of the spindle with movement of the carriage and limit its rotation in said direc tion.

7. In combination, a bed, a cutter on the bed and adapted to rotate and reciprocate, means adatped to reciprocate-the cutter relative to the bed, means adapted to rotate the cutter, a carriage mounted on the bed for reciprocation relative to the cutter, a drive adapted to operate the carriage, a work carrying spindle adapted to rotate, a support rotatably carrying the spindle, means selectively positioning the support on the carriage, means adapted to apply torque to the spindle to yieldingly rotate it in one direction, and a governor connection between the bed and spindle adapted to coordinate rotation of the spindle with movement of the carriage and limit its rotation in said direction.

8. In combination, a bed, a member adapted to reciprocate relative to said bed, a second member adapted to rotate on said bed, a drive normally tending to yieldingly rotate said second member, and a governor control connecting said members including a mechanism controlling speed of rotation of the said second member responsive to and limited by movement of the first mentioned member relative to said bed and means whereby the said second member is rotatively advanced by said drive a predetermined amount each time the first mentioned member reaches a predetermined position in its cycle of operation including an indexing plate adapted to lock the second member in successive positions responsive to reciprocation of the first mentioned member.

9. In combination, a bed, a member adapted to reciprocate relative to said bed, a second member adapted to rotate .on said bed, means adapted to apply torque to the second member to yieldingly rotate it, and a governor control connecting said members including a mechanism controlling speed of rotation of the said second member responsive to and limited by movement of the first mentioned member relative to said bed and an indexing mechanism whereby the said second member is allowed to rotatively advance a predetermined amount each time the first mentioned member reaches a predetermined position in its cycle of operation including an indexing plate adapted to lock the second member in successive positions responsive to reciprocation of the first mentioned member.

10. In combination, a bed, a member adapted to reciprocate relative to said bed, a second member adapted to rotate on said bed, means adapted to apply torque to the second'member to yieldingly rotate it, and a governor control connecting said members whereby rotation of saidsecond member is responsive to and limited by movement of the first mentioned member relative to said bed and said second member advances rotatively a predetermined amount each time the first mentioned member reaches a predetermined position in its cycle of operation, the control including an indexing plate adapted to lock the second member in successive positions and a planetary gear mechanism normally providing a positive gear connection between said members.

11. In combination, a bed, a member adapted to reciprocate relative to said bed, a second member adapted to rotate on said bed, and a governor control connecting said members whereby speed of rotation of said second member is responsive to and limited by movement of the first mentioned member relative to said bed and said second member advances rotatively a predetermined amount each time the first mentioned member reaches a predetermined position'in its cycle of opertion, the control including a drive normally tending to yieldingly rotate the said second member, and a planetary mechanism having a floating ring operating in synchronism with the first mentioned member, a gear operating with the said second member, a gear intermittently rotated responsive to said first mentioned member reaching said position, and a pinion carried by the ring and meshed between said gears.

12. In combination, a bed, a member adapted to reciprocate relative to said bed, a second member adapted to rotate on said bed, and a governor control connecting saidmembers whereby speed of rotation of said second member is responsive to and limited by movement of the first mentioned member relative to said bed and said second member advances rotatively a predetermined amount each time the first mentioned member reaches a predetermined position in its cycle of operation, the control including a drive normally tending to yieldingly rotate the said second member,-and a planetary mechanism having a floating ring, gear means between the ring and the first mentioned member whereby the ring and the first mentioned member operate in synchronism, a gear operating with the said second memher, a gear intermittently rotated responsive to said first mentioned memberreaching 'said position, and a pinion carried by the ring-and meshed between said gears.

13. In combination, a bed, a member adapted to reciprocate relative to said bed,'a second member adapted to rotate on said bed, and a governor control connecting said members whereby speed of rotation of said second member is responsive to and limited by movement of the first mentioned member relative to said bed and said second member advances rotatively a predetermined amount each time the first mentioned member reaches a predetermined position in its cycle of operation, the control including a drive normally tending to yieldingly rotate the said second member, and a planetary mechanism iaving a'fioating ring operating in synchronism with the first'mentioned member, a "gear'operating'with the said 16 second member, a second gear mounted to rotate,and a latch controlling rotation of said second gear responsive to positioning of the first mentioned member, said sec- 0nd gear being rotatably responsive to said first mentioned member reaching said position, and a pinion carried by the ring and meshed between said gears.

14. In combination, a bed, a member adapted to reciprocate relative to said bed, a second member adapted to rotate on said bed, and a governor control connecting said members whereby speed of rotation of said second member is responsive to and limited by movement of the first mentioned member relative to said bed and said second member advances rotatively a predetermined amount each time the first mentioned member reaches a predetermined position in its cycle of operation, the control including a drive normally tending to yieldingly rotate the said second member, and a planetary mechanism having a floating ring operating in synchronism with the first mentioned member, a gear operating with the said second member, a second gear mounted to rotate, a latch controlling movement of the second gear, and operating means adapted to operate the latch and responsive to positioning of the first mentioned member.

15. In combination, a bed, a power driven cutter on the bed, a carriage mounted on said bed for reciprocation relative to the cutter, drive means operating the carriage, a work carrying spindle rotatable on the carriage, means selectively mounting the spindle on the carriage, means tending to yieldingly rotate the spindle in one direction, and a governor control responsive to the carriage and normally controlling the spindle to rotate in synchronism with movement of the carriage and limiting rotative advance of the spindle in the said direction each time the carriage reaches a predetermined position in its cycle of operation.

16. In combination, a bed, a power driven cutter on the bed, a carriage mounted onsaid bed for reciprocation relative to the cutter, drive means operating the carriage, a work carrying spindle rotatable on the carriage, means selectively mounting the spindle on the carriage, means tending to yieldingly rotate the spindle in one direction, and a planetary governor mechanism normally controlling the spindle to rotate in synchronism with movement of the carriage relative to said bed and limiting rotative advance of the spindle in the said direction each time the carriage reaches-a predetermined position in its cycle of operation.

17. In combination, a bed, a power driven cutter on the bed, a carriage mounted on said bed for reciprocation relative to the cutter, drive means operating the carriage, a work carrying spindle rotatable'on the cariage, means selectively mounting the spindle on the carriage, means tending to yieldingly rotate the spindle in one direction, and a latch controlled planetary governor mechanism normally controlling the spindle to rotate in synchronism with movement of the carriage relative to said bed and limiting rotative advance of the spindle in the said direction each time the carriage reaches a predetermined position in its cycle of operation.

18. In combination, a bed, a power driven cutter on the bed, a carriage mounted on'said bed-for reciprocation relative to the cutter, drive means operating the carriage,

a work carrying spindle rotatable on the carriage, means selectively mounting the spindle on the carriage, means tending to yieldingdyrotatc the spindle in one direction, and'a governor control responsive to the carriage and normally limiting the spindle to rotate in said direction in synchronism with movement of the carriage relative to the said bed and effecting rotative advance of the spindle each time the carriage reaches a predetermined position in its cycle of operation, thegovernor control including a planetary mechanism connecting the bed and spindle and having a rotatable gear, a latch normally holding the gear against rotation, and means responsive 17 to positioning of the carriage operating to intermittently release the latch.

19. A machine tool for milling circumferentially spaced grooves in a work-piece including, a frame, a milling cutter rotatably carried by the frame, a carriage reciprocable on the frame and relative to said cutter, a rack fixed to the frame and extending parallel with the table, and a fixture mounted on said carriage for reciprocation therewith, said fixture including a housing, a work carrying spindle rotatably carried by said housing, force transmitting means carried by the housing operatively connecting the frame and said spindle and including a gear meshing with said rack, a gear train operatively connected with said gear, and a planetary gear mechanism operatively connected with the gear train and having a first normally rotating sun gear fast on said spindle, a ring meshed with said gear train, a second normally stationary sun gear, and a planet gear carried by said ring and meshing between said first and second sun gears and adapted to rotate about said second sun gear to effect rotation of said first sun gear and the spindle as the carriage operates. v

20. A machine tool for milling circumferentially spaced grooves in a Work-piece including, a frame, a milling cutter rotatably carried by the frame, a carriage reciprocable on the frame and relative to said cutter, a rack fixed to the frame and extending parallel with the carriage, and a fixture mounted on said carriage for reciprocation therewith, said fixture including a base fixed on said carriage, a housing rotatively adjustable relative to the base about an axis normal of the carriage, releasable clamping means holding the housing stationary relative to the base, a spindle rotatably carried by said housing and adapted to support a work-piece, power means normally applying torque to rotate said spindle, and a gear train between and synchronizing the operation of the carriage relative to the frame with the rotation of the spindle to limit rotation of the spindle.

21. A machine tool for milling circumferentially spaced grooves in a work-piece including, a frame, a milling cutter rotatably carried by the frame, a carriage reciprocable on the frame and relative to said cutter, a rack fixed to the frame and extending parallel with the carriage, a fixture mounted on said carriage for reciprocation therewith and including a housing, a spindlle rotatably carried by said housing and adapted to support a workpiece, force transmitting means carried by the frame operatively connecting the spindle and frame, said means including a gear meshing with said rack and a gear train between said gear and the spindle, and power means normally applying torque to said spindle in a direction to maintain the said force transmitting means under pressure.

22. A machine tool for milling circumferentially spaced grooves in a work-piece including, a frame, a milling cutter rotatably carried by the frame, a carriage reciprocable on the frame and relative to said cutter, a rack fixed to the frame and extending parallel with the carriage, a fixture mounted on said carriage for reciprocation therewith and including a housing, a spindle rotatably carried by said housing and adapted to support a work-piece, force transmitting means carried by the housing operatively connecting the spindle and frame, said means including a gear meshing with said rack and a gear train between said gear and the spindle, and power means normally applying torque to said spindle in a direction to maintain the said force transmitting means under pressure, said power means including a reversible fluid pres sure actuated motor, a worm gear operated by the motor, and a worm wheel on said spindle and meshed with said worm gear.

23. A machine tool for milling circumferentially spaced grooves in a work-piece, including, a frame, a milling cutter rotatably carried by the frame, a carriage reciprocable on the frame in a path normal to the axis of said cutter, fluid pressure actuated means adapted to recipro cate the carriage, a rack fixed to the frame and extending parallel with the path of movement of the carriage, a housing carried by said carriage, a work-holder spindle rotatably carried by said housing, a gear rotatably carried by said housing and meshing with said rack, a gear train in driving engagement with said gear, a planetary mecha nism in driving engagement with said gear train and including a ring tov which the gear train is connected and rotatable about said spindle, a normally stationary gear concentric with the spindle, a gear fixed to and concentric with the spindle, and a planet gear rotatably carried by the ring and meshed with said concentric gears, power means normally tending to yieldingly rotate said spindle and including a reversible fluid actuated motor, a fluid handling system including a pair of pressure lines connected to said motor and a reversible valve in said lines, means operative in response to movement of said carriage actuating said valve including an electrical circuit having a solenoid adapted to actuate said valve, and a switch in said circuit controlling the solenoid and responsive to the position of the carriage relative to the frame.

24. A machine tool for milling circumferentially spaced grooves in a Work-piece including, a frame, a milling cutter rotatably carried by the frame, a carriage reciprocable on the frame in apath normal to the axis of said cutter, fluid pressure actuated means adapted to reciprocate the carriage, a rack fixed to the frame and extending parallel to the path of movement of the carriage, a housing carried by said carriage, a work-holder spindle rotatably carried by said housing, a gear rotatably carried by said housing and meshing with said rack, a power means operative to yieldingly drive said spindle, and a reversible change gear train between said gear and the spindle including gears adapted to effect operation of said gear train in one direction during travel of the carriage through a working stroke,

and gears adapted to effect operation of said gear train in the opposite directionduring said travel'of the carriage.

25. A machine tool for milling circumferentially spaced slots in the periphery of a Work-piece, including, a frame, a carriage movable on the frame in one direction through a working stroke and in the opposite direction through a return stroke, fluid pressure actuated means adapted to move the table in said directions, a milling cutter rotatably carried by said frame, a fixture mounted on said carriage for movement therewith and having a spindle provided with an end for carrying a work-piece to be milled by said cutter upon movement of the carriage relative to the frame through said working stroke, power means carried by said housing operatively connected to said spindle for applying torque thereto, an index plate rotatable coaxially of the spindle and having circumferentially spaced slots therein, connecting means operatively connecting said index plate and said spindle, latching means normally engaging in a slot of said index plate to prevent rotation of said plate, and latch-releasing means operative in response to completion of movement of the carriage relative to the frame through said return stroke to release said latching means so as to allow partial rotation of said spindle under the action of said power means.

26. A machine tool for milling circumferentially spaced slots in the periphery of a work-piece, including, a frame, a carriage movable on the frame in one direction through a working stroke and in the opposite direction through a return stroke, fluid pressure actuated means adapted to move the carriage in said directions, a milling cutter rotatably carried by said frame, a fixture mounted on said carriage for movement therewith, said fixture having a spindle provided with an end for receiving a work-piece to be milled by said cutter upon movement of the carriage relative to the frame through said working stroke, power means carried by said housing operatively connected to said spindle for yieldingly applying torque thereto, an index plate rotatable coaxially of the spindle and having circumferentially-spaced slots therein, connecting means operatively connecting said index plate and said spindle, a

latch engageable in a slot of said index plate to hold the plate against turning, spring means operative to yieldingly maintain said latch normally engaged, a releasable pivoted locking arm engageable with said latch for normally retaining the same in latching engagement with said index plate so as to prevent rotation of said spindle, and latchrcleasing means operative in response to completion of movement of the carriage relative to the frame through said return stroke to release said latch so as to allow partial rotation of said spindle under the action of said power means, said latch-releasing means being rendered inoperative upon start of movement of the carriage through said working stroke so as to effect locking of said index plate by said latch.

27. A machine tool for milling circumferentially spaced slots in the periphery of a work-piece including, a frame, a carriage movable on the frame in one direction through a Working stroke and in the opposite direction through a return stroke, fluid pressure actuated means for moving the carriage in said directions, a milling cutter rotatably carried by said frame, a fixture mounted on said carriage for movement therewith, said fixture including a spindle provided with an end for receiving a work-piece to be milled by said cutter upon movement of the carriage relative to the frame through said working stroke, power means on said housing operatively connected to said spindle for yieldingly applying torque thereto, an index plate rotatable coaxially of the spindle and having circumferentially spaced slots therein, connecting means operatively connecting said index plate and said spindle, a latch pivoted to said housing and having a lug engageable in said slot of said index plate, a spring operative to yieldingly maintain said latch normally in position to effect such engagement, a releasable locking arm pivoted to said housing and engageable with said latch for normally retaining the same in latching engagement with said index plate so as to prevent'rotation of said spindle, latch-releasing means operative in response to completion of movement of the carriage relative to the frame through said return stroke to release said latch so as to allow partial rotation of said spindle under the action of said power means, said latch-releasing means being rendered inoperative upon start of movement of the plate through said working stroke so as to effect locking of said index plate by said latch, said locking arm being engageable with and pivoted by said index plate to a position to lock said latch, a pivoted fluid pressure actuated power unit, and a link pivotally connected to the latch and said unit providing therewith a toggle which when broken allows pivotal movement of the latch toward said index plate under the action of said spring means.

References Cited in the file of this patent UNITED STATES PATENTS 1,215,804 Holden et al. Feb. 13, 1917 1,454,181 Muller May 8, 1923 1,866,348 Ferris July 5, 1932 2,025,902 Roehm Dec. 31, 1935 2,045,685 Archea June 30, 1936 2,330,921 Rickenmann Oct. 5, 1943 2,359,601 Andrew et al. Oct. 6, 1944 2,385,354 Gaudreau Sept. 25, 1945 2,407,970 Andrew et al. Sept. 24, 1946 2,422,414 Hoier June 17, 1947 2,436,406 Snader Feb. 24, 1948 2,472,346 Schindler June 7, 1949 2,528,753 Iessup Nov. 7, 1950 2,565,787 Tennant Aug. 28, 1951 2,587,449 Ericson Feb. 26, 1952 FOREIGN PATENTS 604,909 Great Britain July 13, 1948 

